In the known structures disclosed in JP,A 6-3211 and JP,A 6-186104, when a metallic lead member is insert molded with, e.g., an organic resin material, a small gap generates at the interface between the resin and the metallic lead member due to resin's physical properties, i.e., the difference in coefficient of linear expansion between the resin and a metal and curing shrinkage of the resin itself occurred when the resin temperature is returned to room temperature after melting. In a pressure sensor, especially, hermetic sealing after insert molding of the pressure sensor is important from the viewpoint of ensuring satisfactory sensor characteristics. None of the above-mentioned publications, however, takes into consideration a hermetic sealing structure for reducing the small gap and providing positive sealing.
Also, JP,A 11-304619 and JP,A 2001-330530 propose the use of a protective material, such as a gel, for ensuring hermetic sealing when a metallic lead member is insert molded with, e.g., an organic resin material.